There are many tutorials on the internet for multi-booting unencrypted distros using a single boot partition and chainloading. For example, booting 145 OSes.
Likewise, there are tutorials for multi-booting distros inside LUKS/LVM if multiple (unencrypted) boot partitions are used, by having the main bootloader chainload the bootloaders in the other unencrypted boot partitions. For example, multi-boot on LUKS.
But I have not been able to find any information about multi-booting with these constraints:
- Only one (or none) unencrypted boot partitions
- No external USB keyfile needed
- No manual steps, other than selecting the distro to boot, and entering the LUKS passphrase (only once)
Is it possible, and if so, how?
The partition arrangement I'm thinking of is:
- sda1, boot partition
- sda2, LUKS container
The LUKS container is managed by LVM:
- swap, shared among all distributions
- [ home, shared among all distributions ]
- root1, main distribution, mounting sda1 as /boot
- root2, distribution 2, including encrypted /boot
- root3, distribution 3, including encrypted /boot
The closest information I've been able to find has a lot of manual steps: only bootloader unencrypted.